CN106964759B

CN106964759B - Method and assembly for forming a component having an internal passageway using a core sleeve

Info

Publication number: CN106964759B
Application number: CN201611166599.1A
Authority: CN
Inventors: C.U.哈德维克; S.F.辛普森; J.L.莫罗索
Original assignee: General Electric Co
Current assignee: General Electric Co PLC
Priority date: 2015-12-17
Filing date: 2016-12-16
Publication date: 2020-01-14
Anticipated expiration: 2036-12-16
Also published as: EP3184199B1; JP6877980B2; US10118217B2; JP2017121663A; EP3184199A1; CN106964759A; US20170173666A1

Abstract

The invention relates to a method and an assembly for forming a component with an internal passage using a core sleeve. A mold assembly (301) for forming a member (80) having an internal passage (82) defined therein includes a mold (300) defining a mold cavity (304) therein, and a core sleeve (310) positioned with respect to the mold. The core sleeve includes a hollow structure (320) and an inner core (324), the inner core (324) being disposed within the hollow structure and positioned to define an internal passage within the component when the component material (72) in a molten state is introduced into the mold cavity and cooled to form the component. The jacket core further includes a first coating (362) disposed between the hollow structure and the inner core.

Description

Method and assembly for forming a component having an internal passageway using a core sleeve

Technical Field

The field of the present disclosure relates generally to components having internal passageways defined therein, and more particularly to such components formed with internal passageways lined with coatings.

Background

Some components require internal passages defined therein, for example, in order to perform the intended function. For example, and not by way of limitation, some components (such as hot gas path components of a gas turbine) are subjected to high temperatures. At least some such components have internal passages defined therein to receive a flow of cooling fluid such that the components are better able to withstand high temperatures. For another example, but not by way of limitation, some components are subject to friction at an interface with another component. At least some such components have an internal passage defined therein to receive a flow of lubricant to facilitate reducing friction.

At least some known components having internal passageways defined therein exhibit improved performance of the intended function after the coating is applied to the internal walls defining the internal passageways. For example, but not by way of limitation, some such components are subject to oxidizing and/or corrosive environments, and oxidation and/or corrosion of the inner wall adversely alters the flow characteristics of the internal passageway. For at least some such components, the coating on the inner wall that inhibits oxidation and/or corrosion improves the performance and/or usable operating life of the component. However, it may be difficult or cost prohibitive to apply such coatings completely and/or uniformly to certain internal passages, such as, but not limited to, internal passages characterized by highly non-linear, complex cross-sections, and/or large length to diameter ratios.

Disclosure of Invention

In one aspect, a mold assembly for forming a component having an internal passage defined therein is provided. The mold assembly includes a mold defining a mold cavity therein, and a core positioned with respect to the mold. The core includes a hollow structure and an inner core disposed within the hollow structure and positioned to define an internal passage within the component when the component material in a molten state is introduced into the mold cavity and cooled to form the component. The jacket core further comprises a first coating disposed between the hollow structure and the inner core.

In another aspect, a method of forming a component having an internal passage defined therein is provided. The method includes positioning a core sleeve with respect to a mold. The sleeve core comprises a hollow structure, an inner core arranged in the hollow structure, and a first coating arranged between the hollow structure and the inner core. The first coating layer is formed of a first coating material. The method also includes introducing the component material in a molten state into the mold cavity, and cooling the component material in the cavity to form the component. The inner core is positioned to define an internal passage within the component, and at least a portion of the first coating material lines at least a portion of the internal passage.

Technical solution 1. a mold assembly for forming a component having an internal passageway defined therein, the mold assembly comprising:

a mold defining a mold cavity therein; and

a core positioned with respect to the mold, the core comprising:

a hollow structure;

an inner core disposed within the hollow structure and positioned to define an internal passage within the component when a component material in a molten state is introduced into the mold cavity and cooled to form the component; and

a first coating disposed between the hollow structure and the inner core.

The mold assembly of claim 1, wherein the first coating is disposed on at least a portion of an interior of the hollow structure.

The mold assembly of claim 1, wherein the first coating is formed of a first coating material selected to alter the properties of the internal passageway when the member is formed.

The mold assembly of claim 4, wherein the first coating material is selected from one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

The mold assembly of claim 1, wherein the first coating is one of a plurality of coatings disposed between the hollow structure and the inner core.

The mold assembly of claim 6, wherein the first coating material is selected from the group consisting of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material, and a second of the plurality of coatings comprises a second coating material selected from another of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

The mold assembly of claim 7, wherein a second of the plurality of coating layers comprises a second coating material, the second coating material comprising a bond coating material.

A method of forming a component having an internal passage defined therein, the method comprising:

positioning a core with respect to a mold, wherein the core comprises:

a hollow structure;

an inner core disposed within the hollow structure; and

a first coating disposed between the hollow structure and the inner core, the first coating formed of a first coating material;

introducing a component material in a molten state into a cavity of the mold; and

cooling a component material in the cavity to form the component, wherein the inner core is positioned to define an internal passage within the component, and at least a portion of the first coating material lines at least a portion of the internal passage.

Claim 9 the method of claim 8, wherein positioning the core sleeve comprises positioning the core sleeve including the first coating disposed on at least a portion of an interior of the hollow structure.

The method of claim 8, wherein positioning the core sleeve comprises positioning the core sleeve comprising the first coating material selected from at least one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

The method of claim 11, wherein positioning the mantle core comprises positioning the mantle core comprising the first coating layer that is one of a plurality of coating layers disposed between the hollow structure and the inner core.

The method of claim 12, wherein positioning the core sleeve further comprises positioning the core sleeve comprising the first coating material selected from one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material, and a second of the plurality of coatings is formed from a second coating material selected from another of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

The method of claim 13, wherein positioning the core sleeve further comprises positioning the core sleeve including a second of the plurality of coating layers formed of bond coat material.

Claim 14 the method of claim 8, wherein the method further comprises forming the core sleeve.

The method of claim 15, wherein the inner core is formed from an inner core material, and forming the core sleeve comprises:

applying the first coating to the interior of the hollow structure; and

filling the coated hollow structure with the core material.

Claim 16 the method of claim 15, wherein applying the first coating includes applying the first coating to the hollow structure in a bulk coating process.

The method of claim 16, wherein applying the first coating includes applying the first coating to the hollow structure in at least one of a vapor deposition process and a chemical vapor deposition process.

Claim 18 the method of claim 15, wherein applying the first coating includes applying the first coating to the interior of the hollow structure in at least one of a slurry injection process and a slurry dipping process.

Solution 19 the method of solution 15, wherein the hollow structure is incrementally formed and applying the first coating comprises applying the first coating to a plurality of incremental portions of the hollow structure.

Claim 20 the method of claim 15, wherein applying the first coating includes applying the first coating during an additive manufacturing process.

Claim 21 the method of claim 15, wherein filling the coated hollow structure with the core material comprises injecting the core material into the hollow structure as a slurry.

Drawings

FIG. 1 is a schematic illustration of an exemplary rotary machine;

FIG. 2 is a schematic perspective view of exemplary components for the rotary machine shown in FIG. 1;

FIG. 3 is a schematic perspective view of an exemplary mold assembly for making the component shown in FIG. 2, the mold assembly including a core sleeve positioned about the mold;

FIG. 4 is a schematic cross-sectional view of an exemplary core sleeve for the mold assembly shown in FIG. 3, taken along line 4-4 shown in FIG. 3;

FIG. 5 is a schematic cross-sectional view of another exemplary core set for the mold assembly shown in FIG. 3, taken along line 4-4 shown in FIG. 3;

FIG. 6 is a cross-section of the component of FIG. 2 taken along line 6-6 shown in FIG. 2;

FIG. 7 is a schematic cross-section of a computer design model of a hollow structure for the mold assembly shown in FIG. 2;

FIG. 8 is a flow chart of an exemplary method of forming a component having an internal passage defined therein (such as a component for the rotary machine shown in FIG. 1); and

fig. 9 is a continuation of the flow chart from fig. 8.

Parts list

10 rotating machine

12 air intake section

14 compressor section

16 burner section

18 turbine section

20 exhaust section

22 rotor shaft

24 one burner

36 shell

40 compressor blade

42 compressor stator vane

70 rotor blade

72 stator vane

74 pressure side

76 suction side

78 component material

80 component

82 internal passages

84 leading edge

86 trailing edge

88 root end

89 axes

90 distal end

92 constant distance

94 constant distance

96 blade length

100 inner wall

300 mould

301 mould assembly

302 inner wall

304 mold cavity

306 mold material

310 sleeve core

312 distal portion

314 distal portion

315 part

316 root segment

318 root portion

320 hollow structure

322 first material

324 inner core

326 core material

328 wall thickness

330 characteristic width

360 inside

362 first coating

366 first coating material

372 second coating

376 second coating material

380 outer wall.

Detailed Description

In the following specification and claims, reference will be made to a number of terms, which shall be defined to have the following meanings.

The singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

"optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about", "approximately" and "approximately", are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here, the range limits may be determined throughout the specification and claims. Such ranges may be combined and/or interchanged, and include all the sub-ranges contained therein unless context or language indicates otherwise.

The example components and methods described herein overcome at least some of the disadvantages associated with known assemblies and methods for forming components having coated internal passageways defined therein. Embodiments described herein provide a core sleeve positioned with respect to a mold. The core sleeve includes (i) a hollow structure, (ii) an inner core disposed within the hollow structure, and (iii) a first coating disposed between the hollow structure and the inner core. The inner core extends within the mold cavity to define a location of an internal passage within a component to be formed in the mold. The first coating includes a first coating material. After the molten component material is introduced into the mold cavity and cooled to form the component, at least a portion of the first coating material lines at least a portion of the internal passage.

FIG. 1 is a schematic illustration of an exemplary rotary machine 10 having components for which embodiments of the present disclosure may be used. In the exemplary embodiment, rotary machine 10 is a gas turbine that includes an intake section 12, a compressor section 14 coupled downstream from intake section 12, a combustor section 16 coupled downstream from compressor section 14, a turbine section 18 coupled downstream from combustor section 16, and an exhaust section 20 coupled downstream from turbine section 18. A generally tubular casing 36 at least partially surrounds one or more of the intake section 12, the compressor section 14, the combustor section 16, the turbine section 18, and the exhaust section 20. In an alternative embodiment, rotary machine 10 is any rotary machine to which components forming an internal passageway as described herein are adapted. Further, although embodiments of the present disclosure are described in the context of rotary machines for illustrative purposes, it should be understood that the embodiments described herein are applicable in any context involving components adapted to form internal passages defined therein.

In the exemplary embodiment, turbine section 18 is coupled to compressor section 14 via a rotor shaft 22. It should be noted that the term "coupled," as used herein, is not limited to a direct mechanical, electrical, and/or communicative connection between the components, but may also include an indirect mechanical, electrical, and/or communicative connection between the components.

During operation of the gas turbine 10, the intake section 12 channels air toward the compressor section 14. Compressor section 14 compresses air to a higher pressure and temperature. More specifically, rotor shaft 22 imparts rotational energy to at least one circumferential row of compressor blades 40 coupled to rotor shaft 22 within compressor section 14. In the exemplary embodiment, each row of compressor blades 40 is preceded by a circumferential row of compressor stator vanes 42 extending radially inward from casing 36 that channel the air flow into compressor blades 40. The rotational energy of the compressor blades 40 increases the pressure and temperature of the air. The compressor section 14 discharges compressed air toward the combustor section 16.

In the combustor section 16, the compressed air is mixed with fuel and ignited to generate combustion gases that are channeled towards the turbine section 18. More specifically, the combustor section 16 includes at least one combustor 24, wherein fuel (e.g., natural gas and/or fuel oil) is injected into the air flow and the fuel-air mixture ignites to generate high temperature combustion gases that are channeled towards the turbine section 18.

Turbine section 18 converts thermal energy from the combustion gas stream into mechanical rotational energy. More specifically, the combustion gases impart rotational energy to at least one circumferential row of rotor blades 70 coupled to rotor shaft 22 within turbine section 18. In the exemplary embodiment, each row of rotor blades 70 is preceded by a circumferential row of turbine stator vanes 72 extending radially inward from casing 36 that channel combustion gases into rotor blades 70. Rotor shaft 22 may be coupled to a load (not shown), such as, but not limited to, an electrical generator and/or a mechanical drive application. The exhausted combustion gases flow downstream from the turbine section 18 into an exhaust section 20. The component of the rotary machine 10 is designed as component 80. The components 80 adjacent the path of the combustion gases are subjected to high temperatures during operation of the rotary machine 10. Additionally or alternatively, member 80 includes any member suitably formed with an internal passage defined therein.

FIG. 2 is a schematic perspective view of an exemplary component 80 shown for use with rotary machine 10 (shown in FIG. 1). The member 80 includes at least one internal passage 82 defined therein by an inner wall 100. For example, cooling fluid is provided to the internal passage 82 during operation of the rotary machine 10 to facilitate maintaining the component 80 below the temperature of the hot combustion gases. Although only one internal passage 82 is shown, it should be understood that the member 80 includes any suitable number of internal passages 82 formed as described herein.

The member 80 is formed from the member material 78. In the exemplary embodiment, component material 78 is a suitable nickel-based superalloy. In an alternative embodiment, the component material 78 is at least one of a cobalt-based superalloy, an iron-based superalloy, and a titanium-based superalloy. In other alternative embodiments, the member material 78 is any suitable material that allows the member 80 to be formed as described herein.

In the exemplary embodiment, component 80 is one of a rotor blade 70 or a stator vane 72. In an alternative embodiment, component 80 is another suitable component of rotary machine 10 that is capable of forming an internal passageway as described herein. In still other embodiments, member 80 is any member for any suitable application suitably formed with an internal passage defined therein.

In the exemplary embodiment, rotor blade 70, or alternatively stator vane 72, includes a pressure side 74 and an opposite suction side 76. Each of the pressure side 74 and the suction side 76 extends from a leading edge 84 to an opposite trailing edge 86. Further, rotor blades 70 or alternatively stator vanes 72 extend from a root end 88 to an opposite tip end 90 to define a blade length 96. In an alternative embodiment, rotor blades 70 or alternatively stator vanes 72 have any suitable configuration that is capable of being formed with an internal passage as described herein.

In certain embodiments, the blade length 96 is at least about 25.4 centimeters (cm) (10 inches). Further, in some embodiments, the blade length 96 is at least about 50.8cm (20 inches). In a particular embodiment, the blade length 96 is in a range from about 61cm (24 inches) to about 101.6cm (40 inches). In an alternative embodiment, blade length 96 is less than about 25.4cm (10 inches). For example, in some embodiments, the blade length 96 is in a range from about 2.54cm (1 inch) to about 25.4cm (10 inches). In other alternative embodiments, blade length 96 is greater than about 101.6cm (40 inches).

In the exemplary embodiment, internal passage 82 extends from a root end 88 to a tip end 90. In alternative embodiments, internal passage 82 extends within member 80 in any suitable manner and to any suitable extent that allows internal passage 82 to be formed as described herein. In certain embodiments, the internal passageway 82 is non-linear. For example, the member 80 is formed with a predefined twist along an axis 89 defined between the root end 88 and the tip end 90, and the internal passage 82 has a curved shape complementary to the axial twist. In some embodiments, the internal passage 82 is positioned at a substantially constant distance 94 from the pressure side 74 along the length of the internal passage 82. Alternatively or additionally, the chord of the member 80 tapers between the root end 88 and the tip end 90, and the internal passageway 82 extends non-linearly complementary to the taper such that the internal passageway 82 is positioned at a substantially constant distance 92 from the trailing edge 86 along the length of the internal passageway 82. In alternative embodiments, the internal passage 82 has a non-linear shape that is complementary to any suitable profile of the member 80. In other alternative embodiments, the internal passage 82 is non-linear and not complementary to the profile of the member 80. In some embodiments, having a non-linear shape of the internal passage 82 facilitates meeting preselected cooling criteria for the component 80. In an alternative embodiment, the internal passageway 82 extends linearly.

In some embodiments, the internal passage 82 has a substantially circular cross-section. In an alternative embodiment, the internal passageway 82 has a generally oval cross-section. In other alternative embodiments, internal passage 82 has any suitably shaped cross-section that allows internal passage 82 to be formed as described herein. Further, in certain embodiments, the shape of the cross-section of the internal passage 82 is substantially constant along the length of the internal passage 82. In alternative embodiments, the shape of the cross-section of the internal passage 82 varies along the length of the internal passage 82 in any suitable manner that allows the internal passage 82 to be formed as described herein.

FIG. 3 is a schematic perspective view of a mold assembly 301 for making the component 80 (shown in FIG. 2). The mold assembly 301 includes a core 310 positioned with respect to the mold 300. Fig. 4 is a schematic cross-section of an embodiment of a core sleeve 310 taken along line 4-4 shown in fig. 3. Referring to fig. 2-4, an inner wall 302 of the mold 300 defines a mold cavity 304. The inner wall 302 defines a shape corresponding to the outer shape of the component 80 such that the component material 78 in a molten state may be introduced into the mold cavity 304 and cooled to form the component 80. It should be recalled that, while the component 80 in the exemplary embodiment is a rotor blade 70 or, alternatively, a stator vane 72 in the alternative exemplary embodiment, the component 80 is any component that may be suitably formed with an internal passage defined therein as described herein.

The core 310 is positioned with respect to the mold 300 such that a portion 315 of the core 310 extends within the mold cavity 304. The core sleeve 310 includes a hollow structure 320 formed from a first material 322, an inner core 324 disposed within the hollow structure 320 and formed from an inner core material 326, and at least a first coating 362 disposed between the hollow structure 320 and the inner core 324 and formed from a first coating material 366. More specifically, at least the first coating 326 is disposed radially between the hollow structure 320 and the inner core 324 about a centerline of the hollow structure 320. The inner core 324 is shaped to define the shape of the internal passageway 82, and the inner core 324 of the portion 315 of the sleeve core 310 positioned within the molding cavity 304 defines the location of the internal passageway 82 within the member 80.

The hollow structure 320 includes an outer wall 380 that surrounds the inner core 324 substantially along the length of the inner core 324. The interior 360 of the hollow structure 320 is positioned internally with respect to the outer wall 380 such that the inner core 324 is complementarily shaped by the interior 360 of the hollow structure 320. In certain embodiments, the hollow structure 320 defines a generally tubular shape. For example, and not by way of limitation, the hollow structure 320 is initially formed from a generally straight metal tube that is suitably manipulated into a non-linear shape (such as a curved or angled shape) as desired to define a selected non-linear shape of the inner core 324 and, thus, the internal passageway 82. In alternative embodiments, the hollow structure 320 defines any suitable shape that allows the inner core 324 to define the shape of the internal passage 82 as described herein.

In the exemplary embodiment, hollow structure 320 has a wall thickness 328 that is less than a characteristic width 330 of inner core 324. The characteristic width 330 is defined therein as the diameter of a circle having the same cross-sectional area as the inner core 324. In an alternative embodiment, the hollow structure 320 has a wall thickness 328 that is not less than the feature width 330. The shape of the cross-section of the inner core 324 is circular in the exemplary embodiment of fig. 3 and 4. Alternatively, the shape of the cross-section of the inner core 324 corresponds to any suitable shape of the cross-section of the internal passage 82 that allows the internal passage 82 to function as described herein.

Also in the exemplary embodiment, a first coating 362 is disposed on at least a portion of an interior 360 of hollow structure 320, between hollow structure 320 and inner core 324. In some embodiments, the first coating material 366 is selected to alter the properties of the internal passage 82 after the component 80 is formed, as will be described herein. For example, and not by way of limitation, the first coating material 366 is selected to inhibit oxidation of the component material 78 along the inner wall 100. Additionally or alternatively, but not by way of limitation, the first coating material 366 is selected to inhibit corrosion of the component material 78 along the inner wall 100. Additionally or alternatively, but not by way of limitation, the first coating material 366 is selected to inhibit deposition of carbon or component material 78 along the inner wall 100. Additionally or alternatively, but not by way of limitation, the first coating material 366 is selected to provide a thermal barrier layer for the component material 78 along the inner wall 100. Additionally or alternatively, but not by way of limitation, the first coating material 366 is selected to provide a water vapor barrier for the component material 78 along the inner wall 100. Additionally or alternatively, but not by way of limitation, the first coating material 366 is selected to inhibit wear, such as, but not limited to, erosion, of the component material 78 along the inner wall 100. Additionally or alternatively, the first coating material 366 is selected to be any suitable material that provides or facilitates any other selected feature when the internal passageway 82 is disposed along the internal wall 100.

In certain embodiments, the first coating 362 is one of a plurality of coatings disposed between the hollow structure 320 and the inner core 324. For example, FIG. 5 is a schematic cross-sectional view of another embodiment of a core sleeve 310 taken along line 4-4 shown in FIG. 3. In the exemplary embodiment, core sleeve 310 includes at least a second coating 372 disposed on at least a portion of interior 360 of hollow structure 320 and formed from a second coating material 376, and a first coating 362 radially disposed between second coating 372 and inner core 324. In some embodiments, the first coating 362 is formed of a first coating material 366 selected from at least one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material, and the second coating material 376 is selected from another one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material. In an alternative embodiment, the second coating material 376 is a bond coating material that facilitates bonding the first coating material 366 to at least one of the first material 322 and the component material 78. In other alternative embodiments, the second coating material 376 is any suitable material that allows the core sleeve 310 to function as described herein.

Referring to fig. 2-5, the mold 300 is formed from a mold material 306. In the exemplary embodiment, mold material 306 is a refractory ceramic material selected to withstand the high temperature environment associated with the molten state of component material 78 used to form component 80. In an alternative embodiment, mold material 306 is any suitable material that allows member 80 to be formed as described herein. Further, in the exemplary embodiment, mold 300 is formed from a suitable investment casting process. For example, and not by way of limitation, a suitable mold material (such as wax) is injected into a suitable mold to form a mold (not shown) of the component 80, the mold is repeatedly dipped into a slurry of the mold material 306, which is allowed to harden to produce a shell of the mold material 306, and the shell is dewaxed and fired to form the mold 300. In alternative embodiments, mold 300 is formed by any suitable method that allows mold 300 to function as described herein.

In certain embodiments, the core 310 is fixed relative to the mold 300 such that the core 310 remains fixed relative to the mold 300 during the process of forming the member 80. For example, the core sleeve 310 is fixed such that the position of the core sleeve 310 is not displaced during introduction of the molten component material 78 into the mold cavity 304 around the core sleeve 310. In some embodiments, the core 310 is directly coupled to the mold 300. For example, in the exemplary embodiment, a tip portion 312 of core sleeve 310 is rigidly enclosed in a tip portion 314 of mold 300. Additionally or alternatively, a root portion 316 of the core 310 is rigidly enclosed in a root portion 318 of the mold 300 opposite the tip portion 314. For example, but not by way of limitation, the mold 300 is formed by investment casting as described above, and the core 310 is securely coupled to a suitable form such that the tip portion 312 and root portion 316 extend out of the form while the portion 315 extends within the cavity of the mold. The mold material is injected into the mold around the core 310 such that the portion 315 extends within the mold. Investment casting causes the mold 300 to surround the tip portion 312 and/or the root portion 316. Additionally or alternatively, the core 310 is fixed relative to the mold 300 in any other suitable manner that allows the position of the core 310 relative to the mold 300 to remain fixed during the process of forming the member 80.

The first material 322 is selected to be at least partially absorbable by the molten component material 78. In certain embodiments, the component material 78 is an alloy and the first material 322 is at least one constituent material of the alloy. For example, in the exemplary embodiment, component material 78 is a nickel-based superalloy and first material 322 is substantially nickel such that, when component material 78 in a molten state is introduced into mold cavity 304, first material 322 is substantially absorbed by component material 78. In an alternative embodiment, the component material 78 is any suitable alloy, and the first material 322 is at least one material that may be at least partially absorbed by the molten alloy. For example, the component material 78 is a cobalt-based superalloy, and the first material 322 is substantially cobalt. For another example, the component material 78 is an iron-based superalloy and the first material 322 is substantially iron. For another example, the component material 78 is a titanium-based superalloy and the first material 322 is substantially titanium.

In certain embodiments, the wall thickness 328 is sufficiently thin such that, upon introduction of the component material 78 in a molten state into the mold cavity 304, the first material 322 of the portion 315 of the core sleeve 310 (i.e., the portion extending within the mold cavity 304) is substantially absorbed by the component material 78. For example, in some such embodiments, the first material 322 is substantially absorbed by the member material 78 such that, after the member material 78 cools, no discrete boundaries delineate the hollow structure 320 by the member material 78. Further, in some such embodiments, first material 322 is substantially absorbent such that, after component material 78 cools, first material 322 is substantially evenly distributed within component material 78. For example, the concentration of the first material 322 near the inner core 324 is not detectably higher than the concentration of the first material 322 at other locations of the member 80. For example, without limitation, the first material 322 is nickel and the component material 78 is a nickel-based superalloy, and after the component material 78 cools, no detectably high nickel concentration remains near the inner core 324, resulting in a substantially uniform distribution of nickel throughout the nickel-based superalloy of the formed component 80.

In an alternative embodiment, wall thickness 328 is selected such that first material 322 is not substantially absorbed by component material 78. For example, in some embodiments, first material 322 is not substantially uniformly distributed within component material 78 after component material 78 cools. For example, the concentration of the first material 322 near the inner core 324 may be detectably higher than the concentration of the first material 322 elsewhere in the member 80. In some such embodiments, the first material 322 is partially absorbed by the member material 78 such that, after the member material 78 cools, the discrete boundaries delineate the hollow structure 320 by the member material 78. Further, in some such embodiments, the first material 322 is partially absorbed by the member material 78 such that at least a portion of the hollow structure 320 near the inner core 324 remains intact after the member material 78 cools.

In some embodiments, the first coating material 366 is also at least partially absorbed by the component material 78 when the component material 78 in a molten state is introduced into the mold cavity 304. In some such embodiments, the thickness of the first coating 362 is selected such that the concentration of the first coating material 366 near the inner core 324 is detectably higher than the concentration of the first coating material 366 elsewhere in the member 80. Thus, after the inner core 324 is removed from the member 80 to form the internal passageway 82, the concentration of the first coating material 366 near the inner wall 100 may be detectably higher than the concentration of the first coating material 366 elsewhere on the member 80. Further, in some such embodiments, at least a portion of the first coating material 366 lines at least a portion of the inner wall 100 of the interior passageway 82.

For example, fig. 6 is a cross-section of the component 80 taken along line 6-6 shown in fig. 2, and schematically illustrates a gradient distribution of the first coating material 366 adjacent the inner wall 100. In some such embodiments, the concentration of the first coating material 366 near the inner wall 100 is sufficient such that at least a portion of the first coating material 366 lines at least a portion of the inner wall 100 defining the internal passageway 82. For example, the concentration of the first coating material 366 near the inner wall 100 is sufficient to form a material characteristic associated with the first coating material 366 along the inner wall 100. Thus, the first coating 362 of the core sleeve 310 effectively applies the first coating material 366 to the internal passage 82 during casting of the component 80.

Further, in certain embodiments where the first coating 362 is one of a plurality of coatings of the core 310, additional coating material (such as, but not limited to, the second coating material 376) is distributed about the inner wall 100 in a similar manner. For example, the concentration of the second coating material 376 near the inner wall 100 is sufficient such that at least a portion of the second coating material 376 lines at least a portion of the inner wall 100 that defines the internal passageway 82. As another example, the second coating material 376 is a bond coating material, and the concentration of the second coating material 376 near the inner wall 100 is sufficient to bond the first coating material 366 to the component material 78 and/or the first material 322 near the inner wall 100.

2-5, in some embodiments, the first coating 362 is partially absorbed by the component material 78 such that discrete boundaries delineate the first coating material 366 from the component material 78 after the component material 78 cools. Further, in some such embodiments, the first coating 362 is partially absorbed by the component material 78 such that at least a portion of the first coating 362 near the inner core 324 remains intact after the component material 78 cools. Thus, after the inner core 324 is removed from the member 80 to form the internal passageway 82, at least a portion of the first coating material 366 lines at least a portion of the inner wall 100. Again, the first coating 362 of the core sleeve 310 effectively applies the first coating material 366 to the internal passage 82 during casting of the component 80.

Further, in certain embodiments where the first coating 362 is one of a plurality of coatings of the core sleeve 310, additional coating material (such as, but not limited to, the second coating material 376) is delineated by discrete boundaries and/or remains intact near the inner wall 100 in a similar manner. For example, the second coating material 376 is a bond coating material, and a portion of the second coating 372 remaining intact bonds the first coating material 366 to the component material 78 and/or the first material 322 adjacent the inner wall 100.

In the exemplary embodiment, inner core material 326 is a refractory ceramic material selected to withstand the high temperature environment associated with the molten state of component material 78 used to form component 80. For example, and without limitation, inner core material 326 comprises at least one of silica, alumina, and mullite. Further, in the exemplary embodiment, inner core material 326 is selectively removed from member 80 to form internal passageway 82. For example, and not by way of limitation, the core material 326 is removed from the component 80 by a suitable process that does not substantially degrade the component material 78, such as, but not limited to, a suitable chemical leaching process. In certain embodiments, the core material 326 is selected based on compatibility and/or removability with the component material 78. In an alternative embodiment, inner core material 326 is any suitable material that allows member 80 to be formed as described herein.

In some embodiments, the core sleeve 310 is formed by applying at least a first coating 362 to the interior 360 of the hollow structure 320, and then filling the coated hollow structure 320 with the inner core material 326. For example, in certain embodiments, at least the first coating 362 is applied to the hollow structure 320 in a bulk coating (bulk coating) process, such as, but not limited to, a vapor deposition process or a chemical vapor deposition process. In some such embodiments, the outer wall 380 of the hollow structure 320 is covered such that only the interior 360 of the hollow structure 320 is coated. Alternatively, both the outer wall 380 and the inner portion 360 are coated, and the coating on the outer portion 380 diffuses into the component material 78, such as when the component 80 is cast. In some such embodiments, applying the coating only to the hollow structure 320 allows for the use of a large number of deposition processes without requiring the entire body of the member 80 to be positioned in a deposition chamber, masking the entire exterior surface of the member 80, and/or without having to coat a large exterior surface area of the member 80, thereby reducing the time and cost required to apply the at least first coating 362 as compared to applying the coating to the internal passageways 82 within the member 80 after the member 80 is formed.

Additionally or alternatively, in some embodiments, at least the first coating 362 is applied to the interior 360 of the hollow structure 320 during a slurry injection process, such as, but not limited to, injecting a slurry comprising the first coating material 366 and/or a precursor thereof into the hollow structure 320, thermally treating the slurry to produce the first coating 362, and then removing the remaining slurry from the hollow structure 320. In some such embodiments, applying the coating only to the hollow structures 320 allows for the use of a slurry deposition process without the need to continuously orient the entirety of the member 80 during the heat treatment process to produce a consistent thickness of the first coating 362.

Additionally or alternatively, in some embodiments, at least a first coating 362 is applied to the interior 360 of the hollow structure 320 during slurry injection, such as, but not limited to, dipping the entirety of the hollow structure 320 in a slurry comprising at least a first coating material 366 and/or a precursor thereof. In some such embodiments, the outer wall 380 of the hollow structure 320 is covered such that only the interior 360 of the hollow structure 320 is coated. Alternatively, both the outer wall 380 and the inner portion 360 are coated, and the coating on the outer portion 380 diffuses into the component material 78, such as when the component 80 is cast.

Further, in some embodiments, the hollow structures 320 are formed incrementally, such as by an additive manufacturing process or as sections that are subsequently joined together. In some such embodiments, at least the first coating 362 is applied to the incremental portions of the hollow structure 320 using a suitable application process, such as any of the application processes described above. For example, but not by way of limitation, a slurry injection process is used, and the injection and removal of relatively thick slurry for the incremental portions of hollow structure 320 is more efficient than the injection and removal of relatively thick slurry for the entire internal passage 82 within member 80 after member 80 is formed, particularly but not exclusively for internal passages 82 characterized by a highly non-linear, complex cross-section, and/or a large length to diameter ratio.

Additionally or alternatively, in some embodiments, at least the first coating 362 is applied integrally to the interior 360 of the hollow structure 320 during the additive manufacturing process. For example, referring also to fig. 7, a computer design model of a hollow structure 320 having at least a first coating 362 applied thereto divides into a series of thin parallel planes between the first end 350 and the second end 352 such that the distribution of the first material 322 and the first coating material 366 within the respective planes is defined. A Computer Numerically Controlled (CNC) machine deposits successive layers of the first material 322 and the first coating material 366 from the first end 350 to the second end 352 according to the model slice to form the hollow structure 320. For example, the additive manufacturing process is suitably configured for staggered deposition of various ones of a plurality of metallic materials and/or metallic and ceramic materials, and the staggered deposition is suitably controlled according to a computer design model to produce a defined distribution of the first material 322 and the first coating material 366 in each layer. Three such representative layers are shown as

layers

364, 368, and 370. In some embodiments, the continuous layers comprising the first material 322 and the first coating material 366, respectively, are deposited using at least one of a Direct Metal Laser Melting (DMLM) process, a Direct Metal Laser Sintering (DMLS) process, a Selective Laser Sintering (SLS) process, an Electron Beam Melting (EBM) process, a selective laser melting process (SLM), and a robotic cast extrusion type additive process. Additionally or alternatively, the continuous layers of first material 322 and first coating material 366 are deposited using any suitable process that allows for the formation of hollow structures 320 as described herein.

In some embodiments, the hollow structure 320 and the first coating 362 being formed by an additive manufacturing process allows the hollow structure 320 to be formed with a uniform and repeatable distribution of the first coating material 366 that would be difficult and/or relatively more expensive to produce by other methods of applying the first coating 362 to the hollow structure 320. Correspondingly, forming the hollow structure 320 from an additive manufacturing process allows the component 80 to be formed with a primary distribution of the first coating material 366 near the inner wall 100 (e.g., as shown in fig. 6) that would be difficult and/or relatively more expensive to apply to the internal passage 82 in a separate process after the component 80 is initially formed in the mold 300.

In alternative embodiments, at least first coating 362 is applied to hollow structure 320 in any other suitable manner that allows core 310 to function as described herein. Further, in certain embodiments in which first coating 362 is one of a plurality of coatings of corer 310, additional coatings (such as, but not limited to, second coating 372) are applied to hollow structure 320 in any of the processes described above for first coating 362 and/or in any other suitable manner that allows corer 310 to function as described herein.

After at least first coating 362 is applied to hollow structure 320, in some embodiments, inner core material 326 is injected into hollow structure 320 as a slurry, and inner core material 326 is dried within hollow structure 320 to form core sleeve 310. Further, in certain embodiments, the central structure 320 substantially structurally reinforces the inner core 324, thus reducing potential problems in some embodiments that would be associated with the production, handling, and use of the unreinforced inner core 324 forming the member 80. For example, in certain embodiments, the inner core 324 is a relatively brittle ceramic material with a relatively high risk of cracking, ripping, and/or other damage. Thus, in some such embodiments, the forming and delivering of the sheath core 310 presents a much lower risk of damage to the inner core 324 than if an unsheathed inner core 324 were used. Similarly, in some such embodiments, forming a suitable pattern around a core sleeve 310 to be used for investment casting of the mold 300, such as by injecting a wax pattern material around the core sleeve 310 into a pattern mold, presents a much lower risk of damage to the inner core 324 than using an unsheathed inner core 324. Thus, in certain embodiments, the use of the core 310 presents a much lower risk of failure than the same steps if the unsheathed inner core 324 were used instead of the core 310 to create an acceptable component 80 having the internal passage 82 defined therein. Accordingly, the core sleeve 310 facilitates obtaining advantages associated with positioning the inner core 324 with respect to the mold 300 to define the internal passageway 82 while reducing or eliminating fragility issues associated with the inner core 324.

For example, in certain embodiments, such as but not limited to embodiments in which the member 80 is a rotor blade 70, the characteristic width 330 of the inner core 324 is in the range of from about 0.050cm (0.020 inches) to about 1.016cm (0.400 inches), and the wall thickness 328 of the hollow structure 320 is selected to be in the range of from about 0.013cm (0.005 inches) to about 0.254(0.100 inches). More specifically, in some such embodiments, the feature width 330 is in a range from about 0.102cm (0.040 inches) to about 0.508cm (0.200 inches), and the wall thickness 328 is selected to be in a range from about 0.013cm (0.005 inches) to about 0.038cm (0.015 inches). As another example, in some embodiments, such as, but not limited to, embodiments in which the component 80 is a stationary component (such as, but not limited to, the stator vane 72), the characteristic width 330 of the inner core 324 is greater than about 1.016cm (0.400 inches), and/or the wall thickness 328 is selected to be greater than about 0.254cm (0.100 inches). In alternative embodiments, feature width 330 is any suitable value that allows the resulting internal passage 82 to perform its intended function, and wall thickness 328 is selected to be any suitable value that allows core sleeve 310 to function as described herein.

Further, in certain embodiments, prior to introducing the inner core material 326 into the hollow structure 320 to form the sleeve core 310, the hollow structure 320 is preformed into a selected non-linear shape corresponding to the internal passage 82. For example, the first material 322 is a metallic material that is relatively easily shaped prior to filling the core material 326, thus reducing or eliminating the need to separately form and/or machine the core 324 into a non-linear shape. Furthermore, in some such embodiments, the structural reinforcement provided by the hollow structure 320 allows for the subsequent formation and handling of a non-linear shaped inner core 324 (which would be difficult to form and handle as an unsheathed inner core 324). Accordingly, the core 310 facilitates the formation of the internal passageway 82 with bends and/or other non-linear shapes of increased complexity and/or with reduced time and cost. In certain embodiments, the hollow structure 320 is preformed to correspond to the non-linear shape of the internal passage 82 that is complementary to the contour of the member 80. For example, but not by way of limitation, as described above, the component 80 is one of a rotor blade 70 and a stator vane 72, and the hollow structure 320 is preformed in a shape complementary to at least one of an axial twist and a taper of the component 80.

An exemplary method 700 of forming a component, such as component 80, having an internal passage defined therein, such as internal passage 82, is shown in the flow diagrams of fig. 8 and 9. Referring also to fig. 1-6, exemplary method 700 includes positioning 702 a core, such as core 310, with respect to a mold, such as mold 300. The sleeve core includes a hollow structure, such as hollow structure 320, and an inner core, such as inner core 324, disposed within the hollow structure. The core sleeve also includes a first coating (such as first coating 362) disposed between the hollow structure and the inner core. The first coating is formed of a first coating material, such as first coating material 366. The method 700 also includes introducing 704 a component material in a molten state (such as component material 78) into a mold cavity (such as mold cavity 304), and cooling 706 the component material in the cavity to form the component. The inner core is positioned to define an internal passage within the component, and at least a portion of the first coating material lines at least a portion of the internal passage.

In some embodiments, the step of positioning 702 a corer includes positioning 708 a corer including a first coating disposed on at least a portion of an interior of a hollow structure (such as interior 360).

In certain embodiments, the step of positioning 702 a core sleeve comprises positioning 710 a core sleeve comprising a first coating material selected from one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

In some embodiments, the step of positioning 702 a mantle core comprises positioning 712 a mantle core, the mantle core comprising a first coating layer that is one of a plurality of coating layers disposed between the hollow structure and the inner core. In some such embodiments, the step of positioning 712 the core comprises positioning 714 the core comprising a first coating material selected from one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material, and a second of the plurality of coatings (such as second coating 372) is formed of a second coating material (such as second coating material 376) selected from another one of them: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material. Alternatively, the step of positioning 712 the core comprises positioning 716 the core comprising a second coating formed from a second coating material comprising a bond coating material.

In certain embodiments, the method 700 further includes forming 718 a core sleeve. In some such embodiments, the inner core is formed from an inner core material (such as inner core material 326), and the step of forming 718 the cored includes applying a first coating to an interior of the hollow structure (such as interior 360), and filling 722 the coated hollow structure with the inner core material.

In certain embodiments, the step of applying 720 a first coating includes applying 724 the first coating to the hollow structure in a bulk coating process. In some such embodiments, the step of applying 724 a first coating includes applying 726 the first coating to the hollow structure in at least one of a vapor deposition process and a chemical vapor deposition process.

In certain embodiments, the step of applying 720 the first coating includes applying 728 the first coating to the interior of the hollow structure in one of a slurry injection process and a slurry impregnation process.

In some embodiments, the hollow structures are incrementally formed, and the step of applying 728 a first coating includes applying 730 the first coating to a plurality of incremental portions of the hollow structures.

In certain embodiments, the step of applying 720 a first coating includes applying 732 a first coating to the interior of the hollow structure during the additive manufacturing process.

In some embodiments, the step of filling 722 the coated hollow structure with the core material comprises injecting 734 the core material into the hollow structure as a slurry.

The example components and methods described herein overcome at least some of the disadvantages associated with known assemblies and methods for forming components having coated internal passageways defined therein. Embodiments described herein provide a core sleeve positioned with respect to a mold. The core sleeve includes (i) a hollow structure, (ii) an inner core disposed within the hollow structure, and (iii) a first coating disposed between the hollow structure and the inner core. The first coating comprises a first coating material, and at least a portion of the first coating material lines at least a portion of the internal passage after molten component material is introduced into the mold cavity and cooled to form the component.

The above-described core sleeve provides a cost-effective method for forming a component having a coated internal passage defined therein, particularly, but not limited to, an internal passage characterized by a high degree of non-linearity, a complex cross-section, and/or a large length to diameter ratio. Specifically, the mantle core includes (i) a hollow structure, (ii) an inner core disposed within the hollow structure, and (iii) a first coating disposed between the hollow structure and the inner core. The inner core extends within the mold cavity to define a location of an internal passage within a component to be formed in the mold. After the molten component material is introduced into the mold cavity to form the component, at least a portion of the first coating material lines at least a portion of the internal passage. Thus, the first coating layer, which forms part of the core sleeve, efficiently applies the first coating material to the internal passage when the component is cast.

In addition, and in particular, in certain embodiments, the first coating layer formed as part of the core sleeve allows the coating layer to be applied in a high volume deposition process without the need to position the entirety of the component in the deposition chamber, cover the entire outer surface of the component, and/or coat a large outer surface area of the component, thus reducing the time and cost required to apply the coating layer as compared to applying the coating layer to internal passages within the component after the component is formed. Alternatively, in some embodiments, the first coating layer formed as part of the mantle core allows the coating to be applied in a slurry deposition process without the need to continuously orient the entirety of the component to produce a consistent coating thickness during the heat treatment process.

Exemplary technical effects of the methods, systems, and apparatus described herein include at least one of: (a) reducing or eliminating fragility issues associated with the formation, handling, transportation, and/or storage of cores used to form components having internal passageways defined therein; (b) allows the use of longer, heavier, thinner and/or more complex cores than conventional cores used to form internal passages of the component; and (c) allowing coating of internal passages, particularly but not limited to internal passages characterized by high non-linearity, complex cross-sections, and/or large length to diameter ratios, improving consistency and/or reducing cost.

Exemplary embodiments of a core sleeve are described above in detail. The core sleeve and the methods and systems for using the core sleeve are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the exemplary embodiments can be implemented and utilized in connection with many other applications that are currently configured to utilize cores within mold assemblies.

Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A die assembly (301) for forming a component (80) having an internal passage (82) defined therein, the die assembly comprising:

a mold (300) defining a mold cavity (304) therein; and

a core (310) positioned with respect to the mold, the core comprising:

a hollow structure (320);

an inner core (324) disposed within the hollow structure and positioned to define an internal passage within the component when a component material (78) in a molten state is introduced into the mold cavity and cooled to form the component, and

a first coating (362) disposed between the hollow structure and the inner core.

2. The mold assembly of claim 1, wherein the first coating is disposed on at least a portion of an interior (360) of the hollow structure.

3. The die assembly of claim 1, wherein the first coating is formed of a first coating material (366) selected to alter a property of the internal passage when the component is formed.

4. The mold assembly of claim 3, wherein the first coating material (366) is selected from one of: (i) an oxidation inhibiting material, (ii) a corrosion inhibiting material, (iii) a carbon deposition inhibiting material, (iv) a thermal barrier material, (v) a water vapor barrier material, and (vi) a wear inhibiting material.

5. A method (700) of forming a component (80) having an internal passage (82) defined therein, the method comprising:

positioning a core (310) with respect to a mold (300), wherein the core comprises:

a hollow structure (320);

an inner core (324) disposed within the hollow structure; and

a first coating (362) disposed between the hollow structure and the inner core, the first coating formed of a first coating material;

introducing a component material (78) in a molten state into a mold cavity (304) of the mold; and

cooling the member material in the mold cavity to form the member, wherein the inner core is positioned to define an internal passage within the member and at least a portion of the first coating material lines at least a portion of the internal passage.

6. The method of claim 5, wherein positioning the core sleeve comprises: positioning the core sleeve comprising the first coating disposed on at least a portion of an interior (360) of the hollow structure.

7. The method of claim 5, wherein the inner core is formed of an inner core material (326), the method further comprising forming the sleeve core by:

applying the first coating to the interior of the hollow structure (360); and

filling the coated hollow structure with the core material.

8. The method of claim 7, wherein applying the first coating comprises applying the first coating to the hollow structure in a bulk coating process.

9. The method of claim 7, wherein applying the first coating comprises applying the first coating to the interior of the hollow structure in at least one of a slurry injection process and a slurry dipping process.

10. The method of claim 7, wherein applying the first coating comprises applying the first coating during an additive manufacturing process.